Chances are, when you turn 18, you'll choose a tattoo that might mean the world to you. I prefer large works(minus tribal) pieces on any gender, and its also possible it may effect how you are employed, so think long and hard about the placement. visible and the places that'll stretch if you ever decide to become pregnant.
Also keep in mind tattoos bleed overtime, ultimately they will become a blotch on your skin, so choose size wisely.
Boys and Girls with tattoos are the same as people without, its personal preference, but my boyfriend has one sleeve, half torso and the other forarm with tattoos.